One Man’s 42-Year Mission to Measure Disappearing Glaciers

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BY BEN TRACY, SENIOR CLIMATE CORRESPONDENT ON ASSIGNMENT FOR CLIMATE CENTRAL

In the remote wilderness of Washington State’s North Cascade Mountains, Mauri Pelto has spent more than four decades tracking a slow but devastating transformation — the rapid disappearance of glaciers.

Now 63 years old, Pelto began measuring these icy giants at just 22. He founded the North Cascades Glacier Climate Project in 1984 as a graduate student, committing to return every summer for 50 years. The summer of 2025 marks year 42.

“My life has been shaped by this ice,” Pelto said during a hike to Mount Baker, where he and Senior Climate Correspondent Ben Tracy made their way across one of the region’s remaining glaciers. “We’ve got 6,000 measurements on this glacier,” Pelto added — a number that reflects his meticulous and enduring dedication.

Pelto’s glacier research, which has been featured by NASA and fed into global glacier databases, reveals a stark reality. Of the 47 glaciers he has studied consistently, 12 have disappeared — nine of those in just the past five years. Since he began his work, glaciers in the North Cascades have shrunk by an estimated 40%.

“A decade ago this glacier would have been 50 feet above your head,” he told Tracy. “That much has been lost.”

The United Nations has named 2025 “The Year of the Glacier,” drawing attention to the vital role glaciers play in providing freshwater to billions. These icy formations are often called Earth’s water towers — they store about 70% of the planet’s freshwater. As they vanish, the effects ripple far beyond the mountains: sea levels rise, coastal flooding worsens, and ecosystems suffer.

According to Climate Central, seven of the ten worst years for glacier melt worldwide have occurred since 2010 — a trend driven by human-caused climate change, including warmer summers and drier winters fueled by fossil fuel emissions.

But Pelto’s work isn’t just about data points — it’s also a family legacy.

His daughter, Jill Pelto, has spent 17 summers by his side on these annual expeditions. Now serving as the project’s art director, she combines science with watercolor to bring the data to life. One of her paintings — visualizing temperature rise and glacier loss — even graced the cover of Time magazine.

“Data is a story about something in the real world,” Jill said. “That story has meaning and emotion. And that’s what I’m trying to bring into my art.”

By embedding graphs and scientific findings into beautiful landscapes, Jill hopes to break down barriers for people who might be intimidated by raw statistics. “The average person is not going to read a scientific report, but they will see a painting,” Tracy noted. “And it does impact you in a different way.” Jill replied simply, “Yes. Definitely.”

It’s become a shared mission — not just of scientific importance, but of deep personal significance.

“We do it so seamlessly at this point,” Mauri said, becoming emotional. “Sometimes I don’t know where I start…”

“This bigger project just means so much to us and has shaped our lives,” Jill added. “Sharing that year after year is beyond special.”

Pelto has just eight summers left to fulfill his 50-year promise. And he admits, he’s not sure what it will feel like to not return to these glaciers once it’s done.

“I can't remember what it was like to not come out here,” he said, looking over a landscape that has changed so drastically during his lifetime. “This landscape has been shaped by ice, and so to understand the landscape and the ice, you really have to walk across it.”